Review: "With an SB-800 speedlight as a master controller, up to three separate groups of SB-600, SB-800, or SB-R200 strobes can be controlled independently, each group consisting of an unlimited number of units. Various Nikon cameras with built-in strobes (the D70, D70S, and D200, as of this writing) can also serve as the master controller, with varying degrees of control.
One parting piece of advice about Nikon's Creative Lighting System: Don't play with it until you're ready to buy a complete setup: Once you've experienced its flexibility and the creative power it gives you, you may not be able to live without it!"